Today more than ever before, electronics designers must pack higher powered components closer together in ever-smaller spaces. More power in less space translates to increased power densities, and higher device operating temperature, thereby requiring increased heat dissipation. As temperatures rise, the reliability and functionality of electronic components are impaired dramatically. Experience has shown that more than 50 percent of electronic failures are the result of thermal problems. Traditionally, heat sinks are used to move heat from components generating the heat to an area where the heat can be dissipated to the atmosphere or adequate ventilation can he provided to the heat sink.
Most conventional heat sinks use sore form of mechanical method to attach the heat-generating component to the heat sink. The most common methods are: adhesives, spring clamping devices, or hold-down brackets with a mechanical fastener, such as a bolt. Adhesives have well known disadvantages associated with storage and handling. In those cases not employing adhesives, the heat sinks are usually made of two pieces: a main heat sink body, and a separate retaining clamp. In some cases, the clamp is a flat spring that at least partially surrounds the component and engages detents or notches in the main heat sink body. Alternatively, the retaining clamp may have a hook on one end that engages an aperture in the main body and is secured to the body by a machine screw. In these mechanical devices, the technician topically must assemble the parts and the component, or apply the adhesive by hand. This hand assembly often results in imprecise alignment of the component and the heat sink. Additionally, this hand alignment requires an appreciable amount of time, which slows down production and ultimately increases the cost of the assembly.
For those cases where the heat sink incorporates structural support features for the component, cooperative alignment of the heat sink and the component is essential so that the assembly readily aligns with the intended apertures on the printed wiring board (PWB). This alignment problem may be overcome by allowing some variability in locating the component on the heat sink, i.e., the component may be shifted laterally when in contact with the heat sink so as to align the leads and supports with the appropriate apertures on the PWB. Of course, this variability may lead to a loose junction between the component and the heat sink. While these fastening methods are adequate in retaining the component on the heat sink, there is a significant cost associated with the time it takes an assembler to make the mechanical attachment of the component to the heat sink.
Obviously, conventional heat sinks have been primarily designed with the principal areas of the heat problem and cost in mind. That is, other areas such as component alignment, board positioning, ease of manufacture, complexity of assembly, etc., have not had high importance indices.
Accordingly, what is needed in the art is a low-cost, easy-to-manufacture, and easy-to-assemble heat sink that incorporates component alignment, as well as solderable board positioning and component attachment features for electrical connectivity.